When Seattle Seahawks receiver Paul Richardson made a miraculous, one-handed touchdown catch in his team's playoff opener, then followed it up with another acrobatic grab, plenty of folks watching the game on TV had one simple question: "Who is that guy?"

Happens every season.

Because while even the most casual NFL fan is familiar with certain players on each team — Russell Wilson, the quarterback throwing to Richardson, for example — there are plenty of others on the roster who are relatively, or completely, unknown to even thorough fans.

They're not mysteries to their coaches and teammates, though.

"This is the kind of play we see from him in practice, so it's not unfamiliar," Seahawks coach Pete Carroll said about Richardson. "Some of the plays were circus-like, but he has done that. He's been waiting a long while to help this team and feel significant about that impact and he's done that."

Maybe Richardson will again step out of the shadows Doug Baldwin or Jimmy Graham to make a mark for Seattle against the Atlanta Falcons on Saturday. Or maybe another unheralded player will wind up making a difference.

AP writers who cover each remaining playoff team picked one player who you might not have heard of but could play a key role in the divisional round this weekend:

Why You Should: While Lee had a career year in his first All-Pro season, Church anchored the league's No. 1 rushing defense as a run-stopping safety. He missed all of November with a broken arm, and it was clear that Dallas' D was not as sturdy without him. When Dallas played Green Bay in the regular season, Church intercepted Aaron Rodgers.

What Was Said: "He's got great energy. He's a really good communicator. I think guys respond well to him." — coach Jason Garrett.

Why You Should: Gabriel, a 5-foot-8 speedster who was undrafted out of Abilene Christian, was looking for a job a week before this season began after getting cut by the Cleveland Browns, of all teams. Now he's a threat to go all the way any time he touches the ball, whether via a screen pass or an end-around run, and scored more TDs (7) than Jones (6).

What Was Said: "Everybody could tell from Day One he was a guy who was going to be able to help us in some way." — Ryan.

Why You Should: Shead has been under the radar his whole career, an undrafted guy from Portland State who only this season became a regular starter on a talented defense famous for "Legion of Boom" members Sherman and Chancellor. While Sherman will be counted on to take away one side of the field, Shead is capable of stopping whichever wideout he covers. He was responsible for one of Tom Brady's two interceptions this season.

What Was Said: "He's done a great job adjusting, growing throughout the season, doing his job. He's a technician." — Sherman.

Why You Should: The 6-foot-4 Cook gives Rodgers the kind of athletic target that he hasn't had at tight end in years. Cook's return from an ankle injury that sidelined him in October, when Green Bay lost to Dallas, added an option to the offense, helped open up the middle and gave opposing safeties something else to think about.

What Was Said: "He's a big body. He's tough to cover. He does a good job catching the football and a good job with the ball in his hands." — Rodgers.

Why You Should: Thuney, a rookie, has been a key member of a Patriots offensive line that has allowed just 17 sacks one season after giving up 38. Thuney didn't allow a sack until Week 15. He's also been an ironman, playing 1,114 of 1,118 snaps. If Houston's defense is kept away from Brady, Thuney will part of the reason.

What Was Said: "Being able to stay out there, day after day and week after week, is tough in this league. Joe's done a good job of that, though." — coach Bill Belichick.

Why You Should: Sorensen, a former undrafted free agent out of BYU, might be listed as a backup safety, but he rarely leaves the field. Along with playing special teams, he helps give Berry, Peters and the rest of the defensive backfield a hard-hitting presence. And he is always around the ball, recovering three fumbles and picking off three passes this season, with one returned for a touchdown.

What Was Said: "When the ball is on the ground, he has no fear about going in there and getting it. There's no hesitation. He's got a nose for it, and it just seems like the ball is bouncing to him right now." — special teams coach Dave Toub.

Why You Should: The 6-foot-7 James (Penn State) was simply supposed to be a placeholder until Ladarius Green got healthy. But James became a productive part of Pittsburgh's versatile offense, catching 39 passes and scoring three TDs. His blocking, a weak spot during his rookie season in 2015, is much improved. The proof came when he took on two defenders on Brown's 50-yard catch-and-run score last weekend.

What Was Said: "He's a really cerebral young guy. He takes an analytic approach to getting better." — coach Mike Tomlin.

Why You Should: The 6-foot-4, 260-pound McKinney leads the Texans with 129 tackles, almost twice as many as any teammate on the league's top-ranked defense. He also accumulated five sacks and forced a fumble. Defensive coordinator Romeo Crennel loves that McKinney is able to drop into coverage at his size.

What Was Said: "He's a very instinctive player, so I think that it was only a matter of time before he was going to be playing at a high level." — coach Bill O'Brien.